This invention relates to novel laminate structures of polyurethane or polyisocyanurate resin foam structures and various facer materials. The peel strength of the bond between the foam and facer material in these novel structures is uniformly at least about 1.5 lbs/in. The invention also relates to processes for preparing these laminate structures.
The use of foamed plastic material for insulating purposes in building structures such as exterior or partition walls, bulk heads, ceilings, floors, storage tanks and roof structures is well known as such foamed plastic materials have a very low thermal conductivity. Polyurethane and polyisocyanurate foams offer excellent insulating efficiency (R value) versus other insulating products, but it has been found that the insulating efficiencies of these products tend to decrease with aging. It is believed that this R value decay is due to the permeation of air into the foam cells. The blowing agents typically used in the manufacture of these foams stay trapped in the cells of the foam structure because of their molecular size and low permeation rates. Air, on the other hand, has a high permeation rate compared to the blowing agents and enters the cells, mixing with the blowing agents. Since air has a much higher vapor thermal conductivity than the blowing agents, the R value of the foam is thereby decreased.
In attempts to avoid this problem, the foams can be faced with materials which serve as gas barriers. Typical facer materials include metal foils such as aluminum. Pinholing of the foil facer, damage to the foil during construction and poor adhesion of the foil to the foam surface, however, are factors which allow air to nonetheless reach the foam surface. In order to benefit from the excellent insulating qualities of polyurethane and polyisocyanurate foams, a method for avoiding the aforementioned problems is needed.